As with every clinical study, there may be some risks. Since the fluoroscope emits X-rays, subjects will be exposed to radiation. During fluoroscopy, the actual dose of radiation exposure that will be administered, is within minimal risk limits and will be much lower than those known to produce detectable health effects. For this study, the fluoroscopy machine will be on for up to, but not more than, 3 minutes total and the amount of radiation will not exceed 3 rem which includes the radiation from the standard Xrays. According to published literature, exposure risks below 5-10 rem are minimal. Health effects have not been consistently demonstrated for radiation exposure below 10 rem.